radioactivity and waves

• What are the three types of radiation in the electromagnetic spectrum mentioned?

  Infrared, visible light, ultraviolet
• What type of waves are all electromagnetic waves?

  Transverse waves
• What happens to the wavelength as the frequency of radiation increases?

  The wavelength decreases
• What is the order of electromagnetic waves from longest to shortest wavelength?

  • Radio waves
  • Microwaves
  • Infrared
  • Visible light
  • Ultraviolet
  • X-rays
  • Gamma rays
• What mnemonic can help remember the order of electromagnetic waves?

  Red Men In Vans Use X-ray Glasses
• How do you calculate the frequency of an electromagnetic wave?

  Frequency = wave speed / wavelength
• What changes occur when light is refracted?

  The direction and speed of light change
• What is the aim of the core practical investigating refraction?

  To investigate how light waves change direction
• What are the steps in the method for investigating refraction?

  1. Draw around the glass block on paper
  2. Draw the normal line
  3. Mark angles of incidence
  4. Direct light ray and mark exit point
  5. Measure angle of refraction
  6. Repeat for other angles
• What is the angle of incidence when the light ray travels along the normal?

  0°
• What happens to light when it moves from air into glass?

  It slows down and changes direction
• What is optical density?

  It refers to how much light slows down
• What is the speed of light in a diamond compared to a vacuum?

  About 40% of the speed in a vacuum
• What happens to X-rays and gamma-rays when they reach the Earth's atmosphere?

  They are absorbed by the upper atmosphere
• What are the four behaviors of electromagnetic waves when interacting with materials?

  1. Reflected off a surface
  2. Refracted when moving between materials
  3. Transmitted through a material
  4. Absorbed by different materials
• How does the energy of electromagnetic waves relate to their wavelength?

  Higher frequency waves are more energetic
• What can X-rays and gamma-rays cause in the body?

  Mutations and cancer
• What can UV radiation cause over time?

  Skin cancer and eye conditions
• What is the effect of too much infrared radiation?

  It can cause skin burns
• How do microwaves affect water in the body?

  They heat the water inside our bodies
• What are some uses of electromagnetic radiation?

  • Sterilizing food and medical equipment
  • Detecting cancer
  • Treating cancer
  • Medical X-rays
  • Airport security scanners
  • Detecting forged banknotes
  • Disinfecting water
  • Illumination
  • Photography
  • Cooking
  • Thermal imaging
  • Short-range communications
  • Remote controls
  • Optical fibers
  • Security systems
  • Mobile phones
  • Broadcasting radio and TV
• What happens when electrons jump between energy levels?

  Radiation is absorbed or emitted
• What is the charge of a proton?

  +1
• What is the charge of a neutron?

  0
• Why are atoms neutral?

  Protons and electrons balance charges
• How does the size of a molecule compare to an atom?

  A molecule is about 10 times larger
• What is the relationship between the energy of electromagnetic radiation and the energy levels of electrons?

  Energy must match the difference in levels
• What happens when electrons absorb electromagnetic radiation?

  They move to higher energy levels
• What happens when electrons emit electromagnetic radiation?

  They move to lower energy levels
• What type of radiation is emitted from unstable atomic nuclei?

  High-energy gamma-rays
• How do protons and neutrons occupy energy levels?

  Similar to electrons in atoms
• What is the relationship between energy changes in the nucleus and electron energy levels?

  Nuclear energy changes are greater
• What is the diameter of a molecule compared to an atom?

  About 10 times the diameter of an atom
• What is the relationship between the number of protons and electrons in an atom?

  They are equal in number
• What is the significance of the nucleus in an atom?

  It contains protons and neutrons
• What is the mass distribution in an atom?

  More than 99% of mass is in the nucleus
• How do diagrams of atoms often misrepresent scale?

  They show nuclei much larger than they are
• How many electrons are in the shells of an atom?

  Same as the total number of protons
• What charge do electrons have?

  Negative charge
• Why are atoms always neutral?

  Positive protons cancel negative electrons